The chemical name of levetiracetam, a single enantiomer, is (−)-(S)-α-ethyl-2-oxo-1-pyrrolidine acetamide, its molecular formula is C8H14N2O2 and its molecular weight is 170.21. Levetiracetam is chemically unrelated to existing antiepileptic drugs (AEDs). It has the following structural formula:
Situations in which AED therapeutic drug monitoring (“TDM”) are most likely to be of benefit have been described (Epilepsia, 49(7):1239-1276, 2008). They include (1) when a person has attained the desired clinical outcome, to establish an individual therapeutic concentration which can be used at subsequent times to assess potential causes for a change in drug response; (2) as an aid in the diagnosis of clinical toxicity; (3) to assess compliance, particularly in patients with uncontrolled seizures or breakthrough seizures; (4) to guide dosage adjustment in situations associated with increased pharmacokinetic variability (e.g., children, the elderly, patients with associated diseases, drug formulation changes); (5) when a potentially important pharmacokinetic change is anticipated (e.g., in pregnancy, or when an interacting drug is added or removed); and (6) to guide dose adjustments for AEDs with dose-dependent pharmacokinetics.
Therapeutic drug management of levetiracetam would serve as an excellent tool to ensure compliance in administering chemotherapy with the actual prescribed dosage and achievement of the effective serum concentration levels. The role of TDM for levetiracetam may also be useful in managing patients that are overdosed.
To date no anti-levetiracetam antibody has been produced and no commercially available immunoassay has been developed for levetiracetam.